Forming cigarette paper



Patented Jan. 1 1952 UNITED STATES PATENT OFFICE assignors to EcustaPaper Corporation,

a. corporation of Delaware No Drawing. Application April 25, 1948,Serial No. 685,001

2 Claims. 1

Our invention relates to cigarette paper and more particularly toimproving the burning properties of the paper when the cigarette issmoked so that the resulting ash has desirable properties.

An important feature of our invention is the modifying of the burningproperties of cigarette paper to avoid formation of carbonized paperparticles that commonly appear as black curling ashes. Such ashes tendto flake oif and fall from the cigarette onto the smokers clothes.

We have discovered that by certain chemical treatment, describedhereafter, of the pulp or furnish from which the cigarette paper ismade, the black, falling ashes can be substantially eliminated.Moreover, a clinging, grayish-white ash of pleasing appearance isproduced when the cigarette using this paper is smoked. The ash producedis more cohesivethan usual, and while it may be flicked off easily atthe will of the smoker, it is sufliciently cohesive and integrated toavoid the frequent accidental dropping of the ash on the smokersclothes.

It has been proposed heretofore to improve the burning and ashcharacteristics of cigarette paper by incorporating various types ofchemical compounds, such as for example, water soluble borate,tungstate, sulfate and phosphate salts, in the cigarette paper duringformation of the paper web on the paper machine. Such applications areusually carried out by immersion of the paper web in a bath of thechemicals, or by spraying a solution of the chemicals onto the preformedpaper sheets.

These procedures have several practical disadvantages that hampercommercial production. For example, the drying capacity of the papermachine is substantially reduced by the rewetting of the paper sheetwith the aqueous solution of the chemicals, and non-uniformity ofapplication of the chemicals to the sheet, particularly where thechemicals are applied with a spray. These difficulties cannot be avoidedby introducing the chemicals into the paper stock prior to web formationof the paper machine because of their water soluble character andconsequent loss of these chemicals from the paper furnish before orduring the formation of the paper sheet.

In accordance with our invention we avoid the practical limitations ofthe above prior procedures by utilizing certain chemicals that can beintroduced into the paper furnish in the heater or in the machine stockchest and before the furnish reaches the paper machine. We havediscovered that by incorporating caustic alkali in certain amounts inthe furnish from which the paper is made that the desired improvement inthe ashing qualities of the paper is obtained. The alkali that we havefound commercially advantageous because of its efliciency, availabilityand low cost, is sodium hydroxide. It can be used as such or partiallyor completely neutralized with an acid, preferably phosphoric acid. Thecombination of caustic soda and phosphoric acid has given usparticularly good results from the standpoint of ash appearance andbehavior.

We have found it especially important to add the alkali to the bleachedor to the finished pulp ready for web formation on the paper machine, sothat a certain proportion of that added will be retained in the finishedpaper.

An advantageous procedure for carrying out the process of our inventionis as follows:

To the beaten pulp in the machine stock-chest we add 2 /2% caustic soda(based on weight of pulp) in the. form of a 2% solution. About fifteenminutes after the caustic soda has been mixed into the stock, we add 1%%phosphoric acid (based on weight of pu p) in the form of a solutioncontaining approximately 25% phosphoric acid. The final stock density inthe chest is about 2 /2%. The filler, which is calcium carbonate, is nowadded in the desired proportions, for example, based on fiber, of whichabout 70% will be retained in the paper. This addition may take place inthe chest or in the stock-line between I the Jordan and the papermachine headbox.

The proportions of caustic soda and phosphoric acid in relation to theweight of pulp may be varied. In general we prefer to maintain thecaustic soda usage between and 5% based on weight of pulp; thephosphoric acid may vary from nothing up to an amount equal to that ofthe caustic soda, and preferably about to 5% phosphoric acid, based onweight of pulp fiber.

Caustic soda alone will improve the tendency of the paper ash to clingto the tobacco; the addition of phosphoric acid to the caustic sodatends to reduce the size of the flakes.

If higher quantities of caustic soda and phosphoric acid are used thancorrespond to our upper limits, the paper is apt to be fire-resistant,and to char when the cigarette is smoked. Indeed, the cigarette may goout.

Instead of adding the caustic soda to the pulp in the stock-chest asabove described, all or part of -it may be added to the pulp while thelatter is in the beater, and at any stage of the beating. We have foundthat addition of at least part of the caustic soda early in the beatingoperation tends to reduce the power consumed in beating.

An important practical advantage of our above described process is thatthe improved ashing characteristics of the paper, produced thereby, donot change with the age of the cigarette. This is contrary to some ofthe prior processes for improving cigarette paper which give initialimprovement in ashing properties but which improvements are lost uponageing of the cigarette.

The filler, for example calcium carbonate, mentioned above, is theprincipal ash producing constituent of the cigarette paper, and isrecited in the claims herein as an ash producing filler.

Various modifications and changes may be made in the foregoing process,materials and products, without departing from the spirit and scope ofour invention as defined in the ,appended claims.

We claim:

1. The process for producing cigarette paper which when burned as thewrapper on a cigarette will produce a clinging, grayish-white, ash thatis sufliciently cohesive and integrated to avoid frequent accidentaldropping of the ash, comprising incorporating in the cigarette paperfurnish just prior to sheeting thereof on a cigarette paper makingmachine andwhich furnish contains predominantly cellulosic fibers andcalcium carbonate flller, approximately /2% to 5% of sodium hydroxideand phosphoric acid in an amount of about /z% to about 5%, based uponthe weight of the fiber and in an amount not greater than a the amountof sodium hydroxide, and then sheeting this furnish'on the paper machineand drying the resulting cigarette paper sheet in such a manner that thefinished cigarette paper contains a substantial amount of the reactionproducts of said sodium hydroxide and phosphoric acid.

2. The process for producing cigarette paper which when burned as thewrapper on a cigarette will produce a clinging, grayish-white ash thatis suiliciently cohesive and integrated to avoid frequent accidentaldroppingof the ash, comprising incorporating in the beaten and washedcel- 4 lulosic flber pulp from which the cigarette paper sheet is to beformed, approximately 2 sodium hydroxide, then incorporating in thisfurnish approximately 1 phosphoric acid in the form of a solutioncontaining approximately 25% phosphoric acid, incorporating in thefurnish approximately calcium carbonate filler, and then sheeting thisfurnish on the paper machine and drying the resulting cigarette papersheet so that the finished cigarette paper contains a substan tialamount of the reaction products of said sodium hydroxide and phosphoricacid.

MILTON O. SCHUR.

ROBERT M. LEVY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Technical Association Papers,Series XXI, pgs. 367 to 372 (1938).

Technical Association Papers, Series m, pgs. 464 and 465 (1941).

Technical Association Papers, Series 25, page 327 (1942).

Journal of Physical Chemistry, volume 44, pgs. 535, 536, 539, 542, 570,571 (1940).

Paper Trade Journal, April 11, 1929, page 54.

1. THE PROCESS FOR PRODUCING CIGARETTE PAPER WHICH WHEN BURNED AS THEWRAPPER ON A CIGARETTE WILL PRODUCE A CLINING, GRAYISH-WHITE, ASH THATIS SUFFICIENTLY COHESIVE AND INTEGRATED TO AVOID FREQUENT ACCIDENTALDROPPING OF THE ASH, COMPRISING INCORPORATING IN THE CIGARETTE PAPERFURNISH JUST PRIOR TO SHEETING THEREOF ON A CIGARETTE PAPER MAKINGMACHINE AND WHICH FURNISH CONTAINS PREDOMINANTLY CELLULOSIC FIBERS ANDCALCIUM CARBONATE FILLER, APPROXIMATELY 1/2 TO 5% OF SODIUM HYDROXIDEAND PHOSPHORIC ACID IN AN AMOUNT OF ABOUT 1/2 TO ABOUT 5%, BASED UPONTHE WEIGHT OF THE FIBER AND IN AN AMOUNT NOT GREATER THAN THE AMOUNT OFSODIUM HYDROXIDE, AND THEN SHEETING THIS FURNISH ON THE PAPER MACHINEAND DRYING THE RESULTING CIGARETTE PAPER SHEET IN SUCH A MANNER THAT THEFINISHED CIGARETTE PAPER CONTAINS A SUBSTANTIAL AMOUNT OF THE REACTIONPRODUCTS OF SAID SODIUM HYDROXIDE AND PHOSPHORIC ACID.